Astronomers bring the third dimension to a doomed star's outburst

A new shape model of the Homunculus Nebula reveals protrusions, trenches, holes and irregularities in its molecular hydrogen emission. The protrusions appear near a dust skirt seen at the nebula's center in visible light (inset) but not found in this study, so they constitute different structures. Credit: NASA Goddard (inset: NASA, ESA, Hubble SM4 ERO Team)

(Phys.org) —In the middle of the 19th century, the massive binary system Eta Carinae underwent an eruption that ejected at least 10 times the sun's mass and made it the second-brightest star in the sky. Now, a team of astronomers has used extensive new observations to create the first high-resolution 3-D model of the expanding cloud produced by this outburst.

"Our model indicates that this vast shell of gas and dust has a more complex origin than is generally assumed," said Thomas Madura, a NASA Postdoctoral Program fellow at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and a member of the study team. "For the first time, we see evidence suggesting that intense interactions between the stars in the central binary played a significant role in sculpting the nebula we see today."

Eta Carinae lies about 7,500 light-years away in the southern constellation of Carina and is one of the most massive binary systems astronomers can study in detail. The smaller star is about 30 times the mass of the sun and may be as much as a million times more luminous. The primary star contains about 90 solar masses and emits 5 million times the sun's energy output. Both stars are fated to end their lives in spectacular supernova explosions.

Between 1838 and 1845, Eta Carinae underwent a period of unusual variability during which it briefly outshone Canopus, normally the second-brightest star. As a part of this event, which astronomers call the Great Eruption, a gaseous shell containing at least 10 and perhaps as much as 40 times the sun's mass was shot into space. This material forms a twin-lobed dust-filled cloud known as the Homunculus Nebula, which is now about a light-year long and continues to expand at more than 1.3 million mph (2.1 million km/h).

NASA Goddard astrophysicists Ted Gull and Tom Madura discuss Eta Carinae and their new model of the Homunculus Nebula, a shell of gas and dust ejected during the star's mid-19th century eruption. Credit: NASA's Goddard Space Flight Center

Using the European Southern Observatory's Very Large Telescope and its X-Shooter spectrograph over two nights in March 2012, the team imaged near-infrared, visible and ultraviolet wavelengths along 92 separate swaths across the nebula, making the most complete spectral map to date. The researchers have used the spatial and velocity information provided by this data to create the first high-resolution, fully 3-D model of the Homunculus Nebula. The new model contains none of the assumptions about the cloud's symmetry found in previous studies.

The shape model, which is now published by the journal Monthly Notices of the Royal Astronomical Society, was developed using only a single emission line of near-infrared light emitted by molecular hydrogen gas. The characteristic 2.12-micron light shifts in wavelength slightly depending on the speed and direction of the expanding gas, allowing the team to probe even dust-obscured portions of the Homunculus that face away from Earth.

"Our next step was to process all of this using 3-D modeling software I developed in collaboration with Nico Koning from the University of Calgary in Canada. The program is simply called 'Shape,' and it analyzes and models the three-dimensional motions and structure of nebulae in a way that can be compared directly with observations," said lead researcher Wolfgang Steffen, an astrophysicist at the Ensenada campus of the National Autonomous University of Mexico.

The new shape model confirms several features identified by previous studies, including pronounced holes located at the ends of each lobe and the absence of any extended molecular hydrogen emission from a dust skirt apparent in visible light near the center of the nebula. New features include curious arm-like protrusions emanating from each lobe near the dust skirt; vast, deep trenches curving along each lobe; and irregular divots on the side facing away from Earth.

"One of the questions we set out to answer with this study is whether the Homunculus contains any imprint of the star's binary nature, since previous efforts to explain its shape have assumed that both lobes were more or less identical and symmetric around their long axis," explained team member Jose Groh, an astronomer at Geneva University in Switzerland. "The new features strongly suggest that interactions between Eta Carinae's stars helped mold the Homunculus."

Every 5.5 years, when their orbits carry them to their closest approach, called periastron, the immense and brilliant stars of Eta Carinae are only as far apart as the average distance between Mars and the sun. Both stars possess powerful gaseous outflows called stellar winds, which constantly interact but do so most dramatically during periastron, when the faster wind from the smaller star carves a tunnel through the denser wind of its companion. The opening angle of this cavity closely matches the length of the trenches (130 degrees) and the angle between the arm-like protrusions (110 degrees), indicating that the Homunculus likely continues to carry an impression from a periastron interaction around the time of the Great Eruption.

A 3-D-printed model of the Homunculus Nebula is compared to a Hubble image of the object. Credit: NASA's Goddard Space Flight Center/Ed Campion

Once the researchers had developed their Homunculus model, they took things one step further. They converted it to a format that can be used by 3-D printers and made the file available along with the published paper.

"Now anyone with access to a 3-D printer can produce their own version of this incredible object," said Goddard astrophysicist Theodore Gull, who is also a co-author of the paper. "While 3-D-printed models will make a terrific visualization tool for anyone interested in astronomy, I see them as particularly valuable for the blind, who now will be able to compare embossed astronomical images with a scientifically accurate representation of the real thing."

More information:
This research has been published in Steffen W. el al., 2014, "The three-dimensional structure of the Eta Carinae Homunculus", Monthly Notices of the Royal Astronomical Society, vol. 442, p. 3316-3328, published by Oxford University Press. mnras.oxfordjournals.org/content/442/4/3316

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Well I watched the video but I am not the scientist no. For me it looks like one of those crankpot things with a lot of triple and double talk in him. You might want to skip over no-Skippy's opinion on it because he thinks the whole universe works from magnets everywhere. If you wait for a while maybe a few of the science-smart-Skippys will chime in with a better opinion that isn't from a crankpot.

Dr_toad

Jul 09, 2014

This comment has been removed by a moderator.

Dr_toad

Don't hold me against him Skippy. If you write the foolishment and two peoples notice it that does not mean anybody got together to call it foolishment, it just means two peoples notice it at the same time. Wait a while Cher you might find out more peoples noticing too.

Non Cher, not right now but after I stop being busy I will get back with you, huh? Some of us unscience smart Skippys have to work sometimes, not too much, I'm not complaining no. But if I do not do it now I might get fired from my job and Mrs-Ira-Skippette would never let me hear the end of that one.

Especially in the face of a model which describes reality so much better than the mainstream one

and what model would that be?Surely not EU which makes claims that are physically impossible and easily debunked, or are you referring to creationist claims, which have all the scientific authority as a used car dealer selling pre-owned septic-processed toilet paper... Even the COURT system recognized that creationists have absolutely nothing to do with science, so there is NO science in creation "science" other than the word

I am surprised creationists haven't been sued for false advertising for including a word in their description which has been proven by a court to be a false descriptor

and how is that LaPoint video relevant to the article?IF the find was as important as supposed, why is there no clamor in the physics community?NO PEER REVIEWED publications either.

@ Captain-Skippy, so it was not just me about the video? It seems like crankpot stuffs to me because he keeps saying that ALL the professional science peoples have been misunderstanding everything all along. That always sets off the warning horn for me when they start off saying something like that.

Even when they try to say it nice what they are really saying is "I am so much smarter than all those professional science peoples who spend their whole life working on stuffs because I have discovered something that every single one of them has overlooked going all the way back to Galileo-Skippy and the Newton-Skippy."

And I ain't going to bite that hook from a no name no school no scientist Skippy from the interweb, just like I'm not going to buy his bridge over the Mississippi River in New Orleans or his one in Brooklyn that crosses the East River on the cheap.

Did you not watch Primer Fields??? It explains this in detail and even creates a plasma chamber to show exactly why this happens. Black holes were shown to be as silly as Dark matter.

Yeah I watch him Skippy. It reminded me of the carnival man who shows you the lady turning into the gorilla right before your eyes. But if you liked it I got a whole list of fun to watch youtube silliness.

Oh yeah, I almost forget, Cher I really want to know this. You just joint up today to plug this youtube thing? Or have you been here all along but been only reading not commenting until today? That's the one you are supposed to say if you are like all the other Skippys who just decided to make their first comment about crankpots on the youtube..

And of course the applied sciences people who also understand when a claim made by a theorist fails miserably based on knowledge they have that the theorists don't...as in the "compressibility" of hydrogen for example.

Which one of the theorists is claiming that the hydrogen is not compressible? I haven't seen that one yet. I'll join you in mocking and ridiculing that crankpot-Skippy.

Everybody knows any gas is compressible, or they should know if they are not the crankpot. Compressing the gas (air) to heat him up and then shoving in some oil real quick is how my diesel engines work. The more you compress him, the hotter he gets, and I didn't even need to go to the science school to learn that.

Which one of the theorists is claiming that the hydrogen is not compressible? I haven't seen that one yet. I'll join you in mocking and ridiculing that crankpot-Skippy.

Everybody knows any gas is compressible, or they should know if they are not the crankpot. Compressing the gas (air) to heat him up and then shoving in some oil real quick is how my diesel engines work. The more you compress him, the hotter he gets, and I didn't even need to go to the science school to learn that.

Wow Ira...a scientific fact!! Good for you! Perhaps now you can use the google to see how, under it's own gravity as proposed, it can compress itself enough to initiate fusion and stay cool enough to become dense enough to do this...All of the information you need to see if this is possible is on the google for you...

Non, I did not want a homework test, I just wanted to know which crankpot was claiming that hydrogen can't be compressed? I was going to help you ridicule him..

Wow Ira...a scientific fact!! Good for you! Perhaps now you can use the google to see how, under it's own gravity as proposed, it can compress itself enough to initiate fusion and stay cool enough to become dense enough to do this

Okayeei, I do that. It was easier than I thought it was going to be. The Wiki-Skippy wrote the good article about that.

So now will you tell me which of the theorist-Skippys is the one saying that hydrogen can't be compressed? I been waiting all morning for a crankpot to ridicule so I'm glad we can join forces on that..

Dr_toad

You want him to ridicule himself, eh? He does that when he opines, just wait a minute...

Now I feel silly me. You mean he is the Skippy who thinks hydrogen can't be compressed and get hot? It's not something he wants to be bragging about that ol Ira knows about a science thing that he did not know. I thought everybody knew that any every gas can be compressed and the more you compress him the more hot he gets.

Ira the numbers you need to be concerned with (I told you there was math involved) are in the chart on the side of your Wiki page:http://en.wikiped...Hydrogen

That is not the one I read no. The one about the sun fusion is the one that explains it.

This is what we call a paradox. Hydrogen can't initiate it's own fusion, the law of thermodynamics prevents it.

You are reading the Wiki-Skippy's article wrong or reading the wrong one. The sun fusion one explains it pretty good. You got confused with it. I think you must maybe got the cold fusion stuffs that Socratic-Skippy likes mixed up with the sun hot fusion. If I can understand the Wiki-Skippy explaining it you probably maybe can too.

Bye duphous!

Right back at you couyon again. You want the silly looking pointy cap to wear while you write your foolishment?

Easy Ira. I was referring to that guy you like to hold close as duphous. You didn't have to use the google if you trust the smart skippy's, remember? This was just if you wanted to risk injury and think for yourself.

Okayeei, apology accepted. I always try the google to find things to explain stuffs. The smart-Skippys are just for the back up in case I don't understand the google and how to know who is the crankpot and who is the real science peoples.

Thanks for understanding No Fate, There is much more to what was shown in Primer Fields and with it, you will be able to explain wave particle duality, pulsars, what are now called Black Holes, and apply it to the atomic structures as well. It is all there regardless of the venue it was shown in. And yes Uncle Ira, I do read what is being said and mostly just watch the show. It is, as you demonstrated, a moot point to discuss most of these issues when what I was saying is hard to grasp when you have spent years studying what were presented as absolute facts. It is like convincing someone that gravity is a push and not a pull. Either way, we get the same results and values, but they are very different indeed. Not one person has ever given a reason or shown where the Primer Fields theory is false. Also, to No Fate, good that you see where PF is not EU. They are annoying and do try to claim that PF validates EU and that is simply not so. I assure you that PF had no Trick Photography.

Uncle Ira

The problem with the Primer Fields; where does the astrophysical bowl shaped magnetic come from? The Primer fields guys completely disregard Maxwell and insist magnetic fields exist without currents, that's pseudoscience. There is a natural plasma phenomena which creates these shapes, it is called a Bennett pinch and has been studied for quite some time.

Seeing the above discussion (or, more accurately, ridicule from one side and abuse from the other), it kinda makes me wonder: what is it about absurd crackpot theories that make a certain kind of person support them with religious fervor against the evil "mainstream" of science?

Is it the same kind of thing that drives conspiracy theorists? And if so, what exactly is it that makes a person like that? Boredom? Overactive imagination? Desire for drama? Pathological paranoia?

I simply don't get it. As critical as those people are towards mainstream science, so uncritical they are of fringe/pseudo-science. No mainstream claim can ever be sufficiently supported by evidence according to these people, yet they require nothing even resembling real evidence on the part of the alternatives. What is it that brings about such a schizoid position in people?

what is it about absurd crackpot theories that make a certain kind of person support them with religious fervor against the evil "mainstream" of science?

@ThomasQuinnit starts with a need to belong to something that is greater than themselves. It also ties strongly into ego, personal beliefs as well as internal mental flaws and insecurities.

when someone attacks their position, like when "mainstream" evil physicists (in their POV) attack the known pseudoscience, they are religious in their defense, and that is the BEST way to comprehend their adherence to the subject matter: it is their FAITH (the belief in something that requires NO evidence)they decided that the story is plausible in their mind and therefore irrefutable by anyone else, like arguing with fanatical religious zealots all over the world.

IT is NOT the science or the evidence they are looking at (they cannot see it in their faith induced delusion), it is the attack against their own / their ego / their faith

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